1. Field of the Invention
The invention relates to in-line roller skates and more particularly to a pneumatic in-line skate wheel of integral construction with adjustable performance characteristics.
2. Description of the Prior Art
In-line roller skating combines the excitement of ice skating with the mobility of running. Enabling recreational access to a wide variety of surfaces, the sport allows an individual to traverse sidewalks, roads, and other rollable surfaces. In-line skating owes its name to the wheel configuration of the skate itself. Arranged longitudinally one behind the other, the wheels rotate in the same longitudinally oriented vertical plane, creating an experience similar to ice skating, where the blade resides in one longitudinal plane.
Wheels designed for in-line roller skating often include, generally, a hard plastic hub around which is mounted a soft elastomeric tire. Difficulties in preserving a permanent bond between the tire and hub have led to hub arrangements incorporating flanged rims to sandwich the tire sides. Such rims come in a variety of configurations including flat, slightly convex or V-shaped plates. The rims must securely fasten the tire in place while the wheel assembly undergoes the axial and lateral stresses associated with operation. Continued deformation of a tire during rotation tends to cause slipping and breakage from a wheel hub.
One solution to the hub to tire bonding problem proposed a hub to mechanically lock the tire in place. The hub incorporates two side plates clamped together to contain roller bearings in a track surrounding an axle and at the outer edge clamping against the opposite sides of an annular tire rib. A device of this type is disclosed in U.S. Pat. No. 1,618,496 to Ware. Although beneficial for its intended use, this design is unsatisfactory for present day high performance wheels requiring a positive lock of the tire in position.
Providing a hub and bearing assembly about an axle tube and circumscribed by annular rings, U.S. Pat. No. 1,697,485 to Ware, discloses a different solution to locking a tire to a hub. The annular rings are clamped at their radially outer extremities against the opposite sides of a tire configured with laterally disposed tire seats. Once again, this design, while beneficial, is unsuited for high performance in-line roller skating use.
A recently disclosed solution to the hub breakage problem incorporates a hub having a mounting flange with bores onto which the tire sits. Hub rims sandwich the tire to the mounting flange and hub bolts secure the tire to the annular rim and flange. Although well suited for in-line roller skating due to the structural rigidity brought about by this design, this arrangement fails to provide a structurally sound pneumatic tire arrangement.
The increase in popularity of in-line roller skating among people of all ages and sizes has necessitated the design consideration for a wheel having adjustable performance characteristics. In-line skating wheels generally come in one size with a predetermined tire resiliency. The performance of these tires depends upon many factors, including the skater's weight and skill level, the rolling surface and the weather. A skater's weight and skill level are fairly predictable, enabling the skater to select the proper performing tire to match those considerations. However, the rolling surface and the weather are often unpredictable, thus illustrating the need for a tire having adjustable performance characteristics.
Tire rotation along a surface is the result of friction acting tangent to the point of contact between a tire and a rolling surface, and opposite to the direction of an externally applied force upon the tire. The frictional force inhibits the tire from sliding across the surface thus causing the tire to roll. The magnitude of a frictional force is generally material dependent and proportional to the weight bearing down upon the point of contact. From a performance perspective, friction can be both an asset and a liability. As a positive characteristic, an increase in friction allows a tire to grip a surface more easily, enabling sharper cornering and wet weather use. On the negative side, an increase in friction equates to less speed along a surface. Therefore, it can be seen that a tire capable of adjustably influencing the amount of friction acting on it offers a user flexibility within the tire's performance spectrum.
Although speed and gripping capability are important performance characteristics for an in-line skating wheel, shock absorption is also an important criterion. Energy absorbed by a tire as a result of traversing bumps or rocks is prevented from shocking a users knees, thus avoiding a potentially dangerous situation. Skate wheels currently on the market exhibit a certain amount of resiliency within the tire such that a predetermined amount of shock absorption is available. This predetermined level of absorption is dependent upon a persons weight. Therefore, the need exists for an improved skate wheel capable of offering an adjustable levels of shock absorption protection for individuals of all weights and sizes.
Efforts to solve the problem of shock absorption within a skate wheel have been disclosed in several U.S. patents. These solutions contemplate shock absorbing elements within the tire such as hard or soft annular rings intended to create an annular void encased in the wall of one of such rings to provide some degree of shock absorption. Although beneficial in that a certain amount of protection is afforded, these designs prevent skaters from manually adjusting the level of shock absorption afforded by the wheel.